Phototransistor with Heterogeneous Double Layer Composed of CsPbIxBr3-x Perovskite and in-Ga-Zn-O Semiconductor for Visible Light Detection

All inorganic perovskites with good excellent physical properties received a considerable attention in optoelectronic applications. Despite the high-performance photoelectric properties of CsPbI3 perovskites retaining the α-phase, actual applications of the perovskite film were hindered by the phase instability at ambient conditions. To improve the availability and long-term stability of CsPbI3, multi-anion structures have been studied in the ABX3 structure of CsPbI3. Herein, we suggest inorganic heterojunction with CsPbIxBr3-x and In-Ga-Zn-O (IGZO) semiconductor which applied bi-anion IxBr3-x instead of I3 in CsPbI3. Using this heterojunction, we demonstrate a new phototransistor with a structure of p++ Si / SiO2 / IGZO / CsPbIxBr3-x / Ti-Al-Ti where IGZO is a charge transfort layer and CsPbIxBr3-x is a light absorption layer. The material stable properties of CsPbIxBr3-x were confirmed by changing the ratio of I : Br from 10: 0 to 0:10. When the ratio of CsPbIxBr3-x perovskite I: Br is 8: 2, the inorganic perovskite maintains the black α-phase in the ambient condition. Phototransistor based on CsPbIxBr3-x perovskite/IGZO heterojunction shows excellent responsivities both ultraviolet region and entire visible light region, unlike the single-IGZO phototransistor reacting only in the ultraviolet region. the phototransistor exhibited a resistivity of 26 A/W, a detection of 8.42 x 1014 Jones, and an external quantum efficiency of 51% at the visible light region (620 nm). Specially it showed the excellent stability over 1 month at atmosphere (20 °C, 25 RH%).